title: Requirement of TFIIH kinase subunit Mat1 for RNA Pol II C-terminal domain Ser5 phosphorylation, transcription and mRNA turnover.
abstract: The relevance of serine 5 phosphorylation of RNA polymerase II carboxy-terminal domain during initiation has been difficult to determine in mammalian cells as no general in vivo Ser5 kinase has been identified. Here, we demonstrate that deletion of the TFIIH kinase subunit Mat1 in mouse fibroblasts leads to dramatically reduced Pol II Ser5 phosphorylation. This is associated with defective capping and reduced Ser2 phosphorylation, decreased Pol II progression into elongation and severely attenuated transcription detected through analysis of nascent mRNAs, establishing a general requirement for mammalian Mat1 in transcription. Surprisingly, the general defect in Pol II transcription in Mat1(-/-) fibroblasts is not reflected in the majority of steady-state mRNAs. This indicates widespread stabilization of mRNAs and points to the existence of a regulatory mechanism to stabilize mRNAs following transcriptional attenuation, thus revealing a potential caveat in similar studies limited to analysis of steady-state mRNAs.
authors.affiliation: Institute of Biotechnology, University of Helsinki, PO Box 56 Viikinkaari 9, 00014 University of Helsinki, Helsinki, Finland.
authors.forename: Katja
authors.initials: K
authors.lastname: Helenius
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.forename: Timofey V
authors.initials: TV
authors.lastname: Tselykh
authors.forename: Heli K J
authors.initials: HK
authors.lastname: Pessa
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Frilander
authors.forename: Tomi P
authors.initials: TP
authors.lastname: Mäkelä
mesh_terms: D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics / Q000502:physiology*; D000818:Animals; D018797:Cell Cycle Proteins; D005347:Fibroblasts / Q000378:metabolism; D017353:Gene Deletion; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000235:genetics / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics; D012315:RNA Caps / Q000032:analysis; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing; D020871:RNA Stability; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D051758:Transcription Factor TFIIH / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D018797:Cell Cycle Proteins; D018840:HSP70 Heat-Shock Proteins; C432410:Mnat1 protein, mouse; D021122:Protein Subunits; D016760:Proto-Oncogene Proteins c-fos; D012315:RNA Caps; D012333:RNA, Messenger; D014157:Transcription Factors; D051758:Transcription Factor TFIIH; D012694:Serine; D011494:Protein Kinases; D012319:RNA Polymerase II